Buildings designed for passive solar heating with natural sunlight to light a building’s interior incorporate large south-facing windows, skylights, and building materials that absorb and slowly release the sun’s heat. Incorporating passive solar designs can reduce heating bills as much as 50 percent. Passive solar designs can also include natural ventilation for cooling. Windows are an important aspect of passive solar design. In cold climates, south-facing windows designed to let the sun’s heat in while insulating against the cold are ideal. In hot and moderate climates, the strategy is to admit light while rejecting heat. Interior spaces requiring the most light, heat, and cooling are located along the south face of the building, with less used space to the north. Open floor plans allow more sun inside.
Active Solar Heating
Active solar heating systems consist of collectors that collect and absorb solar radiation and electric fans or pumps to transfer and distribute the solar heat in a fluid (liquid or air) from the collectors. They may have a storage system to provide heat when the sun is not shining.
An active system may offer more flexibility than a passive system in terms of siting and installation.
Heating your home with an active solar energy system can significantly reduce your fuel bills in the winter.
A solar heating system will also reduce the amount of air pollution and greenhouse gases that result from your use of fossil fuels such as oil, propane, and natural gas for heating or that may be used to generate the electricity that you use.
Combined Passive/Active Solar Heating
We have learned to combine passive and active solar elements in our designs because they both have advantages. Passive heating allows us to use building elements (walls, floors, etc.) as heat storage, reducing the requirements for water storage while leaving the advantages of active solar systems.
A cubic foot of water will transport or store 3800 times the amount of heat the same volume of air will. Active solar systems allow the use of water to collect, store and transport heat.
While some of our houses have been completely passive, actually able to meet their heating loads with the elegant simplicity of passive heating, we believe that a combined system is most effective because the increased area of glass amplifies total heating and cooling load, and active systems allow the greatest flexibility of site design, landscaping, and room layout.
One advantage to using the sun to heat your building in New Mexico is that it allows you to use the unique ”solar right of way” law preventing neighbors from shading your collecting surface, and preserving the open spaces to the south of your building.
Sun and Earth are distributors of ezinc Solar Water Heaters. What better way to save money than to use the Sun to heat your water!
Other systems are available as well. We help you decide what’s best for you!
Jim Graham, Contractor/Builder Las Cruces New Mexico
Don and Beatriz Rudisill reach for the highest level of LEED certification
By Bethany Conway, The Las Cruces Bulletin Editor’s note: This is the first article in a series following the construction of Las Cruces’ first Leadership in Energy and Environmental Design (LEED) Platinum Certified home. Though owners Don and Beatriz Rudisill will not know whether they achieve this certification until their home is complete, sharing their story will help others on their journey to becoming green.
For Don Rudisill, the story behind his home at 4367 Isleta Court is in many ways similar to that of “the first penguin.”
Reaching for Leadership in Energy and Environmental Design (LEED) Platinum Certification – never before achieved in southern New Mexico – he is a lot like the first penguin that takes the plunge into cold, unfamiliar territory. “When you watch a film about penguins, most people notice how they bunch up on the edge of the ice. No penguin wants to be the first to jump into the water where unknown dangers may lurk,” Rudisill said, referencing an excerpt from “The Last Lecture” by Randy Pausch. “The same happens with building something new. Many people like the idea of a green home – improved energy efficiency, a healthier home, and improved utilization of the planet’s resources all sound good – but there are many unknowns.”
After two years of intense planning and overcoming many obstacles, Rudisill is blazing a trail for others to follow – a green trail. He will accomplish this with the help of builder Jim Graham of Sun and Earth, who has 30 years of green-building experience.
“It a very ambitious project,” said Miles Dyson, owner of Inspection Connection LC and the only certified Home Energy Rater in Las Cruces. “He has it very well laid out.”
Dyson, southern New Mexico’s go-to guy when it comes to achieving LEED and Build Green New Mexico (BGNM) certification, will inspect the home throughout the entire process. Credit categories for LEED homes include Sustainable Sights, Locations and Linkages, Indoor Environmental Quality, Water Efficiency, Materials and Resources, Awareness and Education, and Energy and Atmosphere.
The trail began when Don and Beatriz Rudisill sat down to create the home’s footprint. The unusual floor plan is partially the result of the couple trying to meet the LEED requirements for passive-solar design. According to the LEED program, the maximum conditioned square footage for a three-bedroom house should be 1,900 square feet. By going above this amount, the couple loses points. By going below it, they gain points.
“We are trying to stay under 1,690 square feet, which gives us three points (toward LEED Platinum Certification),” he said. By creating a storage closet for seasonal clothing near the master bedroom and a sunroom on the southeast side of the house – two areas that will not be heated or air-conditioned – they will be able to add extra space not counted toward their conditioned square footage.
“This is going to generate a lot of solar heat in the winter,” Rudisill said of the sunroom. “During the summer months, we intend just to leave the windows open, and this will be a bonus room. Jim (Graham) is going to put a fan in here because in the winter it will produce surplus heat that we will be able to blow into the house.” Solar hot water panels hidden behind the parapet over the garage roof will provide additional heat.
Another way they were able to gain points and energy efficiency was by keeping all of the hot water within a 20-foot radius. For this reason, the kitchen and bathrooms are all “clustered within the center of the house.”
“If you look at the plans, we had this 20-foot circle drawn, and that created another requirement for the floor plan,” Rudisill said.
When it came to the slab itself, they used 30 percent fly ash – a waste product from coal after it has been burned in a boiler.
Next on the list was the framing, which was done using finger-jointed lumber. “You take scraps that are too small to be used and make a usable piece out of it,” Rudisill said.
When it came to placing the Marvin windows with ULTREX fiberglass frames, Rudisill also had to be very particular in order to gain LEED points. “I put a lot of time into trying to capture the views because we are given glass budgets. You have to keep the glass within a certain percentage,” he said.
One of the most important attributes of the home are the Structured Insulated Panels manufactured by KC Panels of Animas, N.M, which will make up its 4-inch thick walls. Graham said this is the first time he has used the insulated panels. The thermal resistance, or R-value of the panels, is so high they perform almost twice as well as standard 6-inch walls and result in more than 30 square feet of space being shifted from the walls to the available living space. They are held together by polyurethane foam.
“The foam creates a complete seal around the building,” Rudisill said. “So again, through using this one product, we are saving space and improving energy efficiency. The air-tight seal contributes to improved indoor air quality, and the foam has a class-one fire rating, improving the safety of the home.”
From 10 a.m. to 1 p.m. Saturday, April 18, and 1 to 4 p.m. Sunday, April 19, during the Guild of the Las Cruces Symphony Association’s green home tour, titled The Greening of Las Cruces, residents of Las Cruces will get a chance to visit the construction site and view these panels up close.
“I have an interest in trying to get the information out there about what really goes into a well-built house,” said Rudisill, adding that by educating the public he is actually gaining more points toward the home’s certification.
Though the Rudisills are hopeful they will reach their goal, they won’t know if LEED Platinum Certification will be achieved until the project is complete.
“Being the first to attempt the Platinum level means that we have to be the first in the area to earn certain points. One of the areas that we are earning points is by working as an integrated design team. We have been working very hard as a team with Miles, Jim, and several subcontractors all putting their heads together to help ensure that the rating is achieved.”
Assuming they achieve the platinum rating, the Rudisills will receive $9.50 per square foot in tax credits – close to $15,000.